New method of separation of dansyl amino acid (Dns-AA) enantiomers by capillary electrophoresis (CE) using terguride based chiral selectors (CSs) was developed using linear polyacrylamide coated capillaries. Due to high UV absorption of all studied CSs only capillary was filled with CS, while inlet and outlet vials contained buffer solution only. Conditions for baseline separation of all Dns-AA under study have been found. L-Dns-AAs were eluted prior to D-Dns-AAs on all studied CSs. Use of optical antipode of allyl-terguride resulted in reversal of elution order of all Dns-AAs (D-form was eluted prior to L-form). The best enantioselectivity was achieved for hydroxyl group-containing AAs, i.e. serine and threonine. This finding is in good agreement with proposed mechanism of chiral recognition of these AAs determined by X-ray studies. Seven CSs with different N(1)-side chain unit, five of them designed for the preparation of silica based HPLC chiral stationary phases, were tested for their capability to resolve enantiomers of Dns-AAs. Different polarity and hydrophobicity of N(1)-side chains of the CSs resulted in different CS mobilities thus influencing the effective separation time in capillary. 1-(5-aminopentyl)-terguride showed the best enantioseparation and resolution for Dns-AAs studied.
Enantioseparation of dansyl amino acids on terguride-based chiral selectors. Part I: capillary electrophoretic separation
Sinibaldi M;
2003
Abstract
New method of separation of dansyl amino acid (Dns-AA) enantiomers by capillary electrophoresis (CE) using terguride based chiral selectors (CSs) was developed using linear polyacrylamide coated capillaries. Due to high UV absorption of all studied CSs only capillary was filled with CS, while inlet and outlet vials contained buffer solution only. Conditions for baseline separation of all Dns-AA under study have been found. L-Dns-AAs were eluted prior to D-Dns-AAs on all studied CSs. Use of optical antipode of allyl-terguride resulted in reversal of elution order of all Dns-AAs (D-form was eluted prior to L-form). The best enantioselectivity was achieved for hydroxyl group-containing AAs, i.e. serine and threonine. This finding is in good agreement with proposed mechanism of chiral recognition of these AAs determined by X-ray studies. Seven CSs with different N(1)-side chain unit, five of them designed for the preparation of silica based HPLC chiral stationary phases, were tested for their capability to resolve enantiomers of Dns-AAs. Different polarity and hydrophobicity of N(1)-side chains of the CSs resulted in different CS mobilities thus influencing the effective separation time in capillary. 1-(5-aminopentyl)-terguride showed the best enantioseparation and resolution for Dns-AAs studied.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
